Disclosed herein is an apparatus and method that adjusts a fuser nip width for a fuser, such as a fuser used in xerographic or other forms of printing.
Presently, devices such as printers, copiers, multi-function devices, and other devices produce images on media, such as on sheets, paper, transparencies, plastic, cardboard, or other media. These devices mark a media sheet with a latent image using marking material, such as toner, ink jet ink, solid ink jet ink, or other marking materials. The marked media sheet is then fed through a fuser nip that provides pressure and/or heat to the marked media sheet to fuse the latent image on the media sheet. It is difficult to accurately control the settings of the fuser nip. These settings can include pressure, nip width, temperature, fuser speed, and other settings. These settings influence the efficiency of fusing the latent image on the media. Various factors such as fuser roll hardness, which changes over time, variations in fuser nip settings, temperature control device tolerances, and paper weight and size all affect a device's capacity to provide the optimal amount of energy required to accurately fuse an image with consistent results. For example, a fuser should apply uniform heat and pressure to a media sheet across the width and length of the media sheet. The amount of heat and pressure is based on media sheet type, media sheet size, toner density, and other factors.
If the fuser nip width and temperature are not uniform across the length of the fuser, the heat input to the paper will not be uniform across the width of the paper. This results in a non uniform fusing process, which results in image defects and a poor fixed image. Also, if the fuser nip is not uniform across the length of the fuser, one end of the fuser will receive extensive loading, which causes extensive edge wear on that end. This results in shortened fuser roll life from edge wear. Furthermore, a fuser roll or corresponding pressure roll should be relatively soft and deformable to create a sufficient nip width. However, the roll can harden over time. As the roll hardens, the fuser nip width gets smaller, which reduces fusing efficiency.
Thus, there is a need for an apparatus and method that adjusts a fuser nip width.